HVAC life expectancy
I'm working on a tracking document to project the replacement of the HVAC equipment on state owned buildings. Boilers and chillers aside, what is considered the age to change out a system? Keep in mind that the up keep on these appliances has been shaky at best before I arrived. The R22 to 410 factor is going to play a factor now more than in years past as will SEER. Currently I'm working with split systems and RTUs ranging from 1990-2008 model years.
I'm also interested in maybe changing out some units for Daikin splits, but I'm hearing that the average tech wouldn't be able to work on them without factory specific training.
forget the daikin splits, you'll have issues finding qualified service people beginning to end. spend your money on a 'name, quality' machine that is not factory training specific. you'll save big dollars and future headaches.
age of equipment/ replacement...
if it's a split system replace anything that requires more than 6 service calls on 6 different failures in the first 3 years. do this as the failing equipment will not suddenly become reliable, it was not installed properly. it is that simple.
rooftop package equipment regardless of the brand should give you a minimum of 10 years of service with no more than 2 major failures. rtu's should give you 20 years of service with no more than 3 major failures. a major failure = a compressor change.
if your contractor or engineer has chosen correctly your climate should not be a major factor.
the newer, smaller size a/c units - up to 10 tons - try to use rotary compressors. this type can usually take quite a beating. improper maintenance or inept service is less likely to destroy the compressor. unskilled service contractors though will find ways to ruin your day.
as a rule try not to pay too much attention to the seer number. the manufacturer and testing agencies check this under ideal conditions and proper installation, not the real world. a quality brand of a/c unit won't fail as often as bargain machines and one failure will probably wipe out any energy savings you may realize with that super high seer number. this isn't the party line but to be very honest, i pay seer little attention.
Good points by deerwhistle. However, "life of a unit" is a loaded question. You can help yourself by simply keeping them clean....regular filter changes, coil and evap. pans cleanings. Count on at least ten years for light commercial units, if you do that bare minimum. Bad techs are usually dishonest techs. A dishonest tech is going to screw you, no matter what level of training he or she has. For service, go with a local reputable company you can trust. Take advantage of social media and ask other area facility managers, who they recommend. Word of mouth is gold. Get connected.
I maintain many splits installed in the 70s. Checked weekly by "feel and listen" inspections. 50% still working fine. Only reason to replace is rusted drain pan. and probably because these were not trapped correctly.